Suspending device

ABSTRACT

A chipping hammer is suspended in an obliquely downward directed arm that is swingable both laterally and vertically. The feed arm includes a reversible pneumatic jack whose piston rod is rotatable with respect to its cylinder. A holder is mounted on the end of the piston rod by means of a transverse pivot joint. The holder includes a ball bearing that is mounted on the forward portion of the housing of the hammer. A device in the form of a pneumatic jack or balance block is arranged to countervail the weight of the feed arm and the hammer.

llnited States Patent [1 1 Andersson et a1.

[ 1 Mar. 25, 1975 1 SUSPENDING DEVICE [75] Inventors: Sture R. Andersson, Extorp; Heino Elmessaar, Lidingo, both of Sweden 22 Filed: Feb. 20, 1974 2] Appl. No.: 444,130

[30] Foreign Application Priority Data Feb. 28, 1973 Sweden 73028110 [52] US. Cl. 173/38, 173/43 [51] Int. Cl 325d 4/00 [58] Field of Search 173/38, 43, 44, 45, 33; 248/17 [56] References Cited UNITED STATES PATENTS 1,470,838 10/1923 Holmes 173/38 1,971,922 8/1934 Smith 173/44 2,304,845 12/1942 Pegno 173/43 FORElGN PATENTS OR APPLICATIONS 6/1948 Australia 173/38 Primary Examiner-1ames A. Leppink Attorney, Agent, or Firm-Flynn & Frishauf [57] ABSTRACT A chipping hammer is suspended in an obliquely downward directed arm that is swingable both laterally and vertically.,The feed arm includes a reversible pneumatic jack whose piston rod is rotatable with respect to its cylinder. A holder is mounted on the end of the piston rod by means of a transverse pivot joint. The holder includes a ball bearing that is mounted on the forward portion of the housing of the hammer. A device in the form of a pneumatic jack or balance block is arranged to countervail the weight of the feed arm and the hammer.

16 Claims, 12 Drawing Figures PMEMEDHAR25 872 ,93 3 smears FIG. 2 I6 Eag -rl l PATENTEUHARZSIQH FIG. 5

FIGS

SUSPENDING DEVICE This invention relates to a suspending device for a hand-held power hammer.

During chiselling with a conventional pneumatic chipping hammer, the operator usually grips the hammer with one hand and grips the chisel with his other hand. Usually, a feeding force of around 20 kp is required and the chipping is therefore heavy work. It is difficult to isolate the hnandle of the hammer from vibrations since the feeding force is applied directly on the handle. Moreover, the chisel cannot be satisfactorily isolated from vibrations.

The present invention has for its object to make possible the use of a hand-held power hammer without the operator having to carry the weight of the hammer nor to apply the feeding force. The operator is therfore subject to a minimum of vibrations and a greater feeding force can be applied.

Brief Description of the Invention The invention will be described in detail with reference to the accompanying drawings in which FIG. 1 shows a chipping hammer in a suspending device in accordance with the invention.

FIG. 2 shows the chipping hammer partly in section and at a larger scale. 8

FIG. 3 is a view seen as pointed out by the arrows 33 in FIG. 2,

FIG. 4 is a circuit diagram of the chipping hammer and its feeding device,

FIG. 5 shows in a side view another embodiment of the chipping hammer suspending device.

FIG. 6 shows the suspending device and the chipping hammer of FIG. 5 seen from above,

FIG. 7 shows in a longitudinal section the front portion 'of the chipping hammer shown in FIGS. 5 and 6, FIG. 8 is a section taken along line 8-8 in FIG. 7,

FIG. 9 shows a circuit diagram for the controlling of locking devices that are part of the suspending device shown in FIGS. 5-8,

FIGS. 10 and 11 show in a front view and a side view, respectively, an alternative form of a part of the suspending device shown in FIGS. 5-9.

FIG. 12 shows another suspending device according to the invention. Corresponding elements have been given corresponding reference numerals in the various figures.

Detailed Description of Illustrated Embodiments The device shown in FIGS. 1-4 comprises a chipping hammer with a housing 11 that is mounted on the lower end ofan arm 12 formed by a pneumatic feed jack. The arm 12 includes a feed jack comprising a cylinder 14 with a piston 15 on a piston rod 16. The cylinder 14 is vertically swingably mounted in a sleeve 17 by means ofa horizontal pivot 18. The sleeve 17 is journalled on a vertical pivot 19 that is affixed to, for instance, a ceiling. A horizontal tube 20 is welded to this sleeve 17 in order to form a guide for a wheel 21 that rolls on the tube and carries a balance block 22 which has a suspender line 23 that is attached to the end of the piston rod 16 in order to counterbalance the weight of the chipping hammer l1 and the arm 12. The balance block 22 is a conventional balance block, i.e. it is adjustable and includes a spring and its force is substantially constant independently of variations in the length of the line 23 that is pulled out of the block.

As can be seen in FIGS. 2 and 3, the end of the piston rod 16 is pivotably fastened in a holder 13 by means of a pivot 24. The holder 13 includes a ball bearing comprising an outer race 25, an inner race 26 and balls 66. The outer race 25 of the ball bearing is affixed in the holder 13 and the inner race 26 is affixed on the forward portion of the housing 11 of the hammer. The piston rod 16 is turnable with respect to the cylinder 14. Thus, the chipping hammer is universally movably mounted on the feed arm 12, that is, it will be swingable laterally and vertically with respect to the feed arm and it will also be turnable about its longitudinal axis.

In FIG. 2 is also shown a handle 27 that is extended relative to a normal handle. It has two forwardly directed tubes 28. The housing 11 of the hammer has two corresponding rearwardly directed tubes 29, and the tubes 28, 29 are held together by hoses 30 that are forced into the tubes 28, 29. The tubes 28, 29 do not contact each other but the hoses form vibration dampeners at 31. As can be understood from FIGS. 2 and 4,

compressed air is supplied from a main 32, a hose 33 der chamber 36 through a hose so as to provide for the feeding. The hammer piston of the impact motor is designated by 44. In the handle 27 there is a supply valve 37 with a trigger 38. When this trigger 38 is actuated, the hammer is fed forwardly at the same time as its impact motor starts. With another valve 39 on the handle 27, a cylinder chamber 40' for effecting retraction of the feedjack can be pressurized so that the hammer is pulled rearwardly. In its normal position, the valve 39. vents the cylinder chamber 40. With a third valve 41 for a pneumatic jack '42, 58 that controls a chisel holder, the chisel 43 is released to allow for replacement of the chisel.

The device shown in FIGS. 5 and 6 corresponds in many respects to the one shown in FIGS. 1 to 4, but the pivot 19 is fastened on the. outer end of a carrier arm 45 and not affixed directly to the ceiling. The carrier arm 45 is horizontally swingably mounted on a pivot 46 that is affixed to the ceiling, and it has a support 47 on which two wheels 48 are mounted to roll along a circular support frame 49 that is affixed to the ceiling. A disc 50 rotates with the carrier arm 45 and on the support frame 49 there is a braking device with two crossed shoes 51 which are biased by a spring 65 to clamp the disc 50 so as to arrest the carrier arm 45 in any given angular position. A pneumatic jack 52 is connected between the shoes 51 to separate them when it is pressurized, which is most clearly shown in FIG. 9. The spring 65 is shown placed inside the jack 52 in FIG. 9.

There is also a pneumatic locking device for locking the bearing 25, 26 and this locking device locks the bearing when pressurized. It comprises a pneumatic jack 53 that fixes the outer race 25 of the bearing to the housing 11 of the hammer, as can be seen in FIGS. 7 and 9. The two locking jacks 52, 53 are connected in parallel to a common control valve 55 on a lateral handle 56 of the hammer. In FIG. 7 is shownhow the chisel 43 is held. The shank of the chisel has a recess 57 with which a piston 58, slidable in a cylinder 42, normally engages by being constantly loaded by a compression spring. The piston 58 releases the chisel when com pressed air is supplied from the valve 41.

As can be see in FIG. 7, the bearing 25, 26 has been forced onto the part of the housing of the hammer that receives the backward end (the shank) of the chisel 43 and the inner race 26 is axially locked to the housing 11 by means of a snap ring 60. Because the feed jack is attached in this way to the foremost portion of the housing of the hammer and the handles 27 and 56 are long, relatively small forces are needed in order to hold the hammer also when the hammer is horizontally inclined with respect to the feed arm 12.

As previously described, both the impacting and the feeding starts when the trigger 38 is actuated. Then, when the operator releases the trigger 38, the impact motor stops and the upper cylinder chamber 36 of the feed jack is vented through the impact motor. Since the lower cylinder chamber 40 of the feed jack is normally vented and the chipping hammer is balanced by the balance block 22, the chipping hammer can easily be moved and also lifted. The lifting is also made easier because the feed jack 12 is double-acting and is retracted when the valve 39 is actuated. The joint formed by the pivot 18 may be laterally stiff so that the guide bar 20 positively moves conjointly with the horizontal movement of the feed arm. However, it may also be constructed to allow a limited mutual lateral movement between the guide bar 20 and the feed arm 12 since the balance block 22 will always itself pull its guide bar 20 to the position in which the suspender line 23 is vertical. The guide bar 20 and the feed jack 12 can therefore also be individually journalled on the pivot 19.

When using the suspending device shown in FIGS. -9, the operator can swing the carrier arm 45 without moving his hands from the handles 27, 56 since, by actuating the valve 55, he can simultaneously release'the carrier arm 45 and lock the bearing 25, 26. Then, when the hammer is turned horizontally, the feed arm 12 and the carrier arm 45 swing conjointly. When the valve 55 is then released, the carrier arm 45 is locked in its new position simultaneously with the bearing 25, 26 being released.

The pivot 19 can also be mounted on a trolley 61 arranged to roll along a girder 62 as shown in FIGS. and 11. The trolley is locked by a pneumatic locking jack 63 that, suitably, is connected in the same way as the locking jack 52 in the embodiment shown in FIGS.

In the embodiment shown in FIG. 12, the balance block 22 shown in FIG. 5 is replaced by a constantly pressurized pneumatic jack 70 that applies an upward swinging force on the feed arm whereby it countervails the downward swinging force caused by the weight of the hammer and feed arm. The carrier arm 45 is laterally swingable about an axis I and arrestable in the same way as the carrier arm in FIG. 5 although its locking device is not shown. A support 71 is mounted on the outer end ofthe carrier arm 45 to pivot about an axis II which forms a small angle a with the vertical, and the feed arm 12 is mounted in the support 71 to pivot on a pair of horizontal trunnions 72. The counterbalancing jack 70 is also pivotably mounted on the support 71 and its piston rod is pivotably connected to the feed arm 12. The counterbalance is not as good as it is in the embodiments of FIG. 1 or FIG. 5 since the counterbalancing jack 70 does not respond to variations in the length of the feed arm 12. However, an operator may prefer not to have the hammer at poise, but to have the weight of the hammer and the feed arm not fully compensated for by the counterbalancing jack 70 so that the feed arm 12 will normally slowly swing downward when the hammer 11 is released. Therefore, the variations depending on the variable length of the feed arm is a minor disadvantage.

Another balance block 73 is shown in FIG. 12. This balance block is mounted on the feed arm 12 and its suspender line 74 is deviated over a wheel 75 and attached to the handle 27. This balance block 73 is adjusted to pull the handle 27 towards the feed arm 12 when the operator releases the handle and it also prevents the piston rod 16 from falling out rapidly when there is no air pressure acting on the piston. However, it permits the piston rod to extend slowly as a result of the weight of the hammer. Such a balance block 73 can also be used in the suspending devices shown in FIGS. 1 and 5.

What we claim is:

1. A suspending device for a hand-held power hammer, comprising:

a mount,

an obliquely downwardly directed extendible arm pivotably mounted at its upper end to the mount so as to be swingable both laterally and vertically, said arm including a feed jack for extending and retracting said arm,

means for universally movably mounting said hammer to the lower end of said arm, and

a device arranged to apply an upward swinging force on said arm to countervail the downward swinging force caused by the weight of the hammer and the arm.

2. A suspending device according to claim 1 in which said hammer is so mounted in a holder as to be turnable thereinabout its longitudinal axis, said holder being pivotably mounted to the lower end of said arm.

3. A suspending device accordingto claim 2 in which said holder is pivotably mounted to the lower end of said arm so as to be pivotable about an axis transverse to said arm, said lower end of said arm being turnable about an axis parallel with the longitudinal axis of said arm.

4. A suspending device according to claim 3 in which said lower end of said arm is turnable about the longitudinal axis of said arm.

5. A suspending device according to claim 4 in which said feed jack comprises a cylinder and a piston, and said lower end of said arm comprises an extension of a piston rod of said piston, said piston being freely rotatable in said cylinder so as to provide for the turnability of said lower end of the arm.

6. A suspending device according to claim 2 in which the housing of the hammer has a forward portion adapted to receive a chisel, said holder being mounted on said forward portion of the housing of the hammer.

7. A suspending device according to claim 6 in which said holder includes a roller bearing having an outer race, an inner race and rolling elements therebetween, said inner race being affixed on said forward portion of the housing of the hammer.

8. A suspending device according to claim 7 in which said chisel extends backwardly into said housing beyond said bearing.

9. A suspending device according to claim 1 in which said arm is pivotably mounted to a first member so as to be swingable about a horizontal axis, said first member being pivotably mounted in said mount for pivoting about a substantially vertical axis.

10. A suspending device according to claim 9 in which said substantially vertical axis forms a small angle with the vertical.

11. A suspending device according to claim 1 in which the hammer has a pneumatic impact motor and the feed jack is a pneumatic jack that extends when a first cylinder chamber is pressurized, said impact motor and said cylinder chamber being connected in parallel to a normally open supply control valve disposed on the hammer.

12. A suspending device according to claim 11 in which the feed jack has a second cylinder chamber for retracting the jack when pressurized, said second cylinder chamber being connected to a control valve that has a normal position for venting said second cylinder chamber and a position for pressurizing the same.

13. A suspending device according to claim 2 in which said mount is horizontally movably arranged and arrestable by means of a first pneumatically operated locking device, and a second pneumatic locking device is arranged for locking the hammer against turning relative to said holder, one of said locking devices locking when pressurized, the other releasing when pressurized, said locking devices being connected in parallel to a common control valve.

14. A suspending device according to claim 1 in which the feed jack is a double-acting pneumatic jack and the hammer is mounted to the piston rod of said jack, a spring device being operatively coupled between the cylinder of the jack and the piston rod of the jack.

15. A suspending device according to claim 14 in which said spring device comprises a balance block fastened to the cylinder of the feed jack and having its line,

deviated over a wheel and fastened to the hammer, said wheel being fastened to the piston rod whereby to provide for said line simultaneously tending to pull the hammer towards the piston rod and tending to retract the piston rod into the cylinder.

16. A suspending device for a hand-held pressure fluid operated percussive tool, comprising:

a carrier arm mounted to be swingable about a vertical axis and having a free end,

- an obliquely downwardly directed extendible feed arm having one end so mounted to the free end of said carrier arm as to be swingable both laterally and vertically relative thereto, said feed arm including a pressure operatedfeed jack for extending and retracting said feed arm,

means for universally movably mounting said percussive tool to the lower end of said feed arm, and a device arranged to countervail the weight of said feed arm and said percussive tool.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENTNO.: 3,872,933

DATED March 25, 1975 INVENTOR(S) I Sture R. ANDERSSON et a1 It is certified that error appears in the above-identified patent and that said Letters Patent v are hereby corrected as shown below:

Column 6, line 21 after "a pressure" insert --fluid-.

Signed and sealed this 10th day of June 1975..

(SEAL) Attest: r

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. A suspending device for a hand-held power hammer, comprising: a mount, an obliquely downwardly directed extendible arm pivotably mounted at its upper end to the mount so as to be swingable both laterally and vertically, said arm including a feed jack for extending and retracting said arm, means for universally movably mounting said hammer to the lower end of said arm, and a device arranged to apply an upward swinging force on said arm to countervail the downward swinging force caused by the weight of the hammer and the arm.
 2. A suspending device according to claim 1 in which said hammer is so mounted in a holder as to be turnable therein about its longitudinal axis, said holder being pivotably mounted to the lower end of said arm.
 3. A suspending device according to claim 2 in which said holder is pivotably mounted to the lower end of said arm so as to be pivotable about an axis transverse to said arm, said lower end of said arm being turnable about an axis parallel with the longitudinal axis of said arm.
 4. A suspending device according to claim 3 in which said lower end of said arm is turnable about the longitudinal axis of said arm.
 5. A suspending device according to claim 4 in which said feed jack comprises a cylinder and a piston, and said lower end of said arm comprises an extension of a piston rod of said piston, said piston being freely rotatable in said cylinder so as to provide for the turnability of said lower end of the arm.
 6. A suspending device according to claim 2 in which the housing of the hammer has a forward portion adapted to receive a chisel, said holder being mounted on said forward portion of the housing of the hammer.
 7. A suspending device according to claim 6 in which said holder includes a roller bearing having an outer race, an inner race and rolling elements therebetween, said inner race being affixed on said forward portion of the housing of the hammer.
 8. A suspending device according to claim 7 in which said chisel extends backwardly into said housing beyond said bearing.
 9. A suspending device according to claim 1 in which said arm is pivotably mounted to a first member so as to be swingable about a horizontal axis, said first member being pivotably mounted in said mount for pivoting about a substantially vertical axis.
 10. A suspending device according to claim 9 in which said substantially vertical axis forms a small angle with the vertical.
 11. A suspending device according to claim 1 in which the hammer has a pneumatic impact motor and the feed jack is a pneumatic jack that extends when a first cylinder chamber is pressurized, said impact motor and said cylinder chamber being connected in parallel to a normally open supply control valve disposed on the hammer.
 12. A suspending device according to claim 11 in which the feed jack has a second cylinder chamber for retracting the jack when pressurized, said second cylinder chamber being connected to a control valve that has a normal position for venting said second cylinder chamber and a position for pressurizing the same.
 13. A suspending device according to claim 2 in which said mount is horizontally movably arranged and arrestable by means of a first pneumatically operated locking device, and a second pneumatic locking device is arranged for locking the hammer against turning relative to said holder, one of said locking devices locking when pressurized, the other releasing when pressurized, said locking devices being connected in parallel to a common control valve.
 14. A suspending device according to claim 1 in which the feed jack is a double-acting pneumatic jack and the hammer is mounted to the piston rod of said jack, a spring device being operatively coupled between the cylinder of the jack and the piston rod of the jack.
 15. A suspending device according to claim 14 in which said spring device comprises a balance block fastened to the cylinder of the feed jack and having its line deviated over a wheel and fastened to the hammer, said wheel being fastened to the piston rod whereby to provide for said line simultaneously tending to pull the hammer towards the piston rod and tending to retract the piston rod into the cylinder.
 16. A suspending device for a hand-held pressure fluid operated percussive tool, comprising: a carrier arm mounted to be swingable about a vertical axis and having a free end, an obliquely downwardly directed extendible feed arm having one end so mounted to the free end of said carrier arm as to be swingable both laterally and vertically relative thereto, said feed arm including a pressure operated feed jack for extending and retracting said feed arm, means for universally movably mounting said percussive tool to the lower end of said feed arm, and a device arranged to countervail the weight of said feed arm and said percussive tool. 